In order to protect themselves from electric shock when working on electrical wiring, electricians need to turn off the electrical power and to be sure that no one else can turn the power back on. Fuses must be removed or circuit breakers must be shut off before electrical work can proceed. If someone replaces the fuse or turns the circuit breaker on while the electrical work is being done, the electrician can be injured or killed by electric shock.
In addition, users of critical equipment are fearful that accidental shutdowns may have severe consequences. Some examples would be the accidental shutdown of: hospital equipment serving an operating room or life support system; airport equipment for air traffic control or communication equipment used by emergency personnel.
The present invention is a solution to both of these problems. Electricians can turn off the circuit breakers they need to work on, lock the electrical panel door with the electrical panel lockout using their own lock. They can be confident that no one will turn those circuit breakers back on while work is being performed. Users of critical equipment can prevent accidental shutdowns by keeping unauthorized persons from entering the electrical panels controlling said equipment by installing the electrical panel lockout with their own lock.
Prior art patents which seek to provide solutions to these problems can be seen in the U.S. Pat. No. 3,044,815, to Soss, for a latching mechanism wherein a panel door can be locked with a key. In the U.S. Pat. No. 5,147,991, to Jordan, Sr., an electrical switch locking system locks a circuit breaker with a padlock. In the U.S. Pat. No. 5,419,165, to Perkins, an electrical panel locking apparatus has a pair of sliding iron bars that clip around the outside of the panel door and are locked in place with a padlock.
To limit the number of persons having access to circuit breakers or fuses, many electrical panel doors are equipped with a latching mechanism that can be locked with a key. One problem with these locks is that many people have the keys for them. The keys for most panel doors from particular electrical panel manufacturers are keyed alike so that electricians, maintenance people and others can have access to a locked panel. Another problem is that access to the circuit breakers can be gained even without a key by simply removing the screws that attach the panel cover to the panel backbox and removing the panel cover and door.
Electrical switch locking systems, also known as circuit breaker lockouts, can be used to lockout a circuit breaker in the off position. They are commonly used by electricians but they have many shortcomings. First, although these devices are claimed to be universal, they are not. There are many different types and sizes of circuit breakers due to amperage ratings, voltage ratings, the number of poles and different manufacturer's models. An electrician must have every different type of circuit breaker lockout available to be able to lockout each particular circuit breaker. Second, each circuit breaker lockout requires its own lock. Many locks will be needed when a number of breakers need to be shut off. This can be quite cumbersome. Third, when the circuit breaker lockout and lock is installed, the panel door cannot be closed. Other circuit breakers in the panel are left accessible to others. It is not desirable to have circuit breakers controlling critical equipment left accessible because of an open panel door. Fourth, while installing circuit breaker lockouts and locks there is the possibility of accidentally shutting off an adjacent circuit breaker causing an equipment shut down. Fifth, many circuit breaker lockouts are flimsy. They fall off or can be easily removed. Sixth, circuit breaker lockouts cannot be used to lock a circuit breaker in the on position. If a circuit breaker was locked in the on position, it could not trip and would not provide the over-current protection that is needed.
The electrical panel locking apparatus is designed to lock an electrical panel door closed but it has some shortcomings. First, being made of iron makes the apparatus heavy and unlikely to be carried by an electrician with his or her standard tools. Also, iron is a conductor of electricity. Many situations require that a panel that needs to be locked is in an electrical closet with other panels and switches. This other equipment may be open with live electricity present. It can be dangerous to employ an iron device in the vicinity of live electrical equipment. Second, during installation this device needs to extend beyond the panel being locked. Thus it can not be used on a panel that is located in a corner next to a wall, or, on a panel located next to another electrical panel or other equipment. These conditions occur often in crowded electrical closets. Third, access to the circuit breakers or fuses can be obtained by removing the panel cover screws and the panel cover thereby defeating the apparatus' intent.
In contrast to these prior art devices, the present invention provides a lightweight and universal method to lockout both circuit breakers and fuses. The key used to lock the device is the user's own key. The device locks the electrical panel door closed and locks the panel cover onto the panel backbox. The device is tamperproof so that it can not be removed without the key. The device can be used on most electrical panels regardless of the electrical panel's proximity to adjacent panels or walls. The device is simple and economical to produce.
It is therefore an object of the invention to lock an electrical panel door with the users own lock. The circuit breakers can then be locked in the desired on or off positions. Fuses can be locked in the installed state or the removed state.
It is another object of the invention to be tamperproof. The device encapsulates two of the electrical panel screws rendering them inaccessible so that the panel cover cannot be removed.
It is another object of the invention to provide an electrical panel lockout device that is portable. The device is lightweight and small enough to fit in an electrician's tool bag when retracted.
It is another object of the invention to be a universal lockout device. The electrical panel is designed to fit various sized panels. Hollow tube extension fittings extend the length of the electrical panel lockout to fit larger panels while maintaining portability.
It is another object of the invention to be usable on most electrical panels regardless of the panel's proximity to walls or other equipment. The device does not extend beyond the width of the electrical panel being locked, either during the installation or after it is installed.
It is another object of the invention that it can be made of a material that is safe to use in all applications. When used in close vicinity to live open electrical equipment, the device can be constructed of PVC, polyvinyl chloride hollow tube, which does not conduct electricity. Where live open electrical equipment is not present, the device can be made from metal hollow tube.
It is another object of the invention is to be affordably priced. The simple design of the device makes it inexpensive to produce.